SITOKIN
·
Sekresi protein
yang mengatur sistem imun, inflamasi dan hematopoiesis.
·
Sitokin bekerja
dalam waktu yang singkat, jarak antar sel yg dekat, dan dalam jumlah
(konsentrasi) yang sangat kecil.
·
Sitokin bekerja
dengan melekat pada membran reseptor yang spesifik, kemudian memberi sinyal
pada sel imun melalui second messenger.
·
Sitokin cepat
disintesis dan disekresikan oleh sel yg berbeda setelah ada stimulus.
·
Sekresi sitokin
o
Limfosit
à limfokin
o
Monosit
àmonokin
o
Sitosin yg aktif
dlm khemotaktik à khemokin
o
Sebagai media
antar leukosiT à interleukin (IL)
·
Aktivitas sitokin
o
Berefek thdp sel
yg mensekresinya sendiri à autokrin
o
Berefek thdp sel
didekatnya à parakrin
o
Berefek pada sel
yg sama tp berjauhan à endokrin
o
Produser sitokin
paling banyak à sel –Th dan makrofag.
·
Terdapat 2 macam sel T-helper:
o
Sel T-h1:
§ Bekerjasama dengan IFNgama, TNF alfa & gama,
IL-2.
§ Yaitu mengatur aktivasi makrofag dan sel T.
o
Sel T-h2:
§ Bekerjasama dengan IL-4, IL-5, IL-6, dan IL-10.
§ Sel-B mediated imunity.
·
Kemokin : mempengaruhi pergerakan leukosit serta
merangsang leukosit pada jaringan yng inflamasi ato infeksi
·
Reseptor sitokin brdasrkan struktur dan aktivitasnya
:
o
Fam hematopoietin
o
Fam interferon
o
Fam. Tumor
Necrosis Factor (TNF
o Fam khemokin
·
Interleukin-1
o
Its initial discovery was as a factor that
could induce fever, control lymphocytes, increase the
number of bone marrow
cells and cause degeneration of bone joints.
o
It was around
1984-1985 when scientists confirmed that IL-1 was actually composed of two
distinct proteins, now called IL-1α
and IL-1β
·
TNF
o
They are produced
also by a broad variety of other cell types including lymphoid cells, mast cells, endothelial cells, cardiac myocytes, adipose tissue, fibroblasts, and neuronal tissue.
o
TNF is able to
induce apoptotic cell
death, to induce inflammation,
and to inhibit tumorigenesis
and viral replication.
o
Dysregulation of
TNF production has been implicated in a variety of human diseases, as well as cancer.
·
Interferons
(IFNs)
o
other functions:
they activate immune cells, such as natural killer cells
and macrophages; they
increase recognition of infection or tumor cells by up-regulating antigen presentation
to T lymphocytes;
o
they increase the
ability of uninfected host cells to resist new infection by virus.
·
Types of IFN
o
other functions:
they activate immune cells, such as natural killer cells
and macrophages; they
increase recognition of infection or tumor cells by up-regulating antigen presentation
to T lymphocytes;
o
they increase the
ability of uninfected host cells to resist new infection by virus.
0 komentar:
Posting Komentar